RE: Knife edge trimming question  
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All Forums >> RC Airplanes >> Pattern Flying >> RE: Knife edge trimming question
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RE: Knife edge trimming question - 5/21/2008 6:06:35 PM   
dick Hanson



Posts: 10028
Joined: 12/12/2001
From: slc, UT, USA
Status: online
quote:

ORIGINAL: flyncajun

Hi Dick,
it seems we have had this aurgument together about 10 years ago
Nat told Me the same thing about 20 years ago.
I think you need to wait for the video
yeah!,you can make it fly with a 1/4 deg of inc.<in the big wing up front> as you put it , But ,OH! No!
I can`t do a knife edge loop without tons of mixing or an upline snap and stay on line,
Oh Yeah and my left rudder knife edge wanders all over the place
come to think of it so does my upline and the down lines
in the world of FAI these things have to be perfect or ,you give up points
only a few guys in the US can make it look" Good" with that set up ,Brett ,Jason, Chip
don`t forget ,,I owned one of your TIPO`S
it`s where I started this Effort 20years ago
I tell you what ,,,go try my method , give it an Honest effort and, report back to the list, then poo! poo! it if you can,
everybody I have helped has had solid results. with a very skepticle reaction at first, you might even be able to come off of your expo a little.
I already used your method ,,,it don`t work, so I developed mine
Sorry Dick, it`s a different Era !
may-be you would be more help teaching me how to spell ,,no that s a loosing battle LOL!
Bryan






Well I could not make sense out of that posting but you shift things around however you like - it's your model
The "perfect pattern plane" is a moving target -and 90% a subjective thing -
You don't like my approach?
Your choice -
What is a skepticle? A deep bowl where you store ideas you don't accept?


_____________________________

I am watching you
Libby

(in reply to flyncajun)
       Post #: 26

RE: Knife edge trimming question - 5/22/2008 3:58:28 AM   
Imac Kiwi



Posts: 317
Joined: 3/7/2003
From: Tg, NEW ZEALAND
Status: offline 		Thanks Bryan for your input, there are a lot of us out here who appreciate it.

I am just putting an Integral together and will try your set-up. It makes a lot of sense and explains a lot about why my last 2M Patternship flew the way it did.

(in reply to dick Hanson)
       Post #: 27

RE: Knife edge trimming question - 5/22/2008 5:25:19 AM   
anuthabubba


 

Posts: 174
Joined: 11/9/2007
From: Transylvania, LA, USA
Status: offline 		I used Bryan's method (+ inc. and CG fwd) on my G3.5 sims and it worked to neutralize the coupling on several planes. Joe Bridi specified a half degree positive in the wing on the Dirty Birdy (just checked the plans to confirm my faded memory). I have long considered his DB flights, that I observed at Lake Charles, as some of the smoothest I ever witnessed. Not saying that it wasn't mostly piloting skill. Never could convince myself to build in that (what seemed excessive) positive incidence though. Until now. Thanks Bryan.

Terry in LP

(in reply to Imac Kiwi)
       Post #: 28

RE: Knife edge trimming question - 5/22/2008 5:57:43 AM   
flyncajun


 

Posts: 120
Joined: 12/25/2006
From: DENHAM SPRINGS , LA, USA
Status: offline 		I know you don`t understand what I wrote Dick,
because you don`t want to ,,,
it`s not 90% Taste, perception,or subjectivity it`s 100% fact
a wing has to produce lift ,,so I add positive inc. in the wing ,,not the fuse ,,like your set up requires.The airplane don`t know up,down sidways ECT we do ,
it flys the same in all positions.
yes,, we do chase these things around for the perfect design,,,,,, Every two years,,
thats when the pattern changes. whats good for one set of manuvers may not be optimum for others so we
adjust the design every two years to accomodate this.
Still Scepticle or should I say Skeptical see I told you you could help with spelling LOL.
So Prove me wrong ,,, use my methods and report back to the list ,,,Scared ?
BY THE WAY,, down here in Cajun Country a Deep Bowl is for storing a chicken and Sausage Gumbo.

I challange you to try it 1/2 deg pos. to the centerline of the fuse start there,,and play around with it.
Airfoil thicknes ,wing design and arcraft weight has a lot to do with this.oh yeah you will have to take out some of your downthust also.
tinker with C/g a little, ,on the exact placement ,that may be a matter of tast I`ll concide to that
see if you can prove "my" unaccepted Idea`s wrong
then we can have a debate on the facts

Dick, I know your a tinkerer what could it hurt?,
Bryan
,,


(in reply to dick Hanson)
       Post #: 29

RE: Knife edge trimming question - 5/22/2008 10:18:22 AM   
alpbak


 

Posts: 41
Joined: 4/27/2006
From: istanbul, TURKEY
Status: offline 		I thanked Bryan earlier in this forum, but after seeing some negative posts I would like to thank him again for helping me out with his article. I had some other trimming charts, especially the "NSRCA Trimming Chart" was really helpful. But I came to a point where none of the trim charts explained what I was experiencing, that is the left rudder tuck. I asked fellow pattern fliers and other experienced modelers around here but I could not get a satisfactory answer and a solution. So I decided to ask the question here on RC Universe and Mike Pascale recommended Bryan's article.

The article made a great sense in general and besides, pointed my exact problem. So, I had no other choice but to try the method. I followed it to the end and VOILA! I have a perfect flying pattern plane.

As I said in my opening post I can trim everything out electronically but this is not the way it should be, IMHO. I should not be depended on the transmitter's abilities to correct the plane's faults. The faults should be corrected mechanically and transmitter should assist me in flight with special thingies like dual rates, exponential etc.

I am not against using the electronic mixing and all other stuff that transmitters offer. And of course if you can not correct a fault mechanically whatever you do, you have to use the transmitter. But if you can create a neutral plane with mechanical adjustments than it is a great satisfaction.

One last thing, I believe that experience is everything in life and we should all try to learn from other's experiences, so that, we do not have to invent the light bulb again all by ourselves. Thanks again to Bryan for sharing his experiences with us, they surely help someone, sometime, somewhere.

Alp

(in reply to flyncajun)
       Post #: 30

RE: Knife edge trimming question - 5/22/2008 12:26:18 PM   
mups53


 

Posts: 1088
Joined: 1/15/2002
From: Hoffman Estates, IL, USA
Status: offline 		Bryan the Chicago Mafia is on board with your suggestions. We all have copies and are going to follow the rules.
The guy who is bombing this thread with negativity has done it time and time again. I think he get's jealous when someone has an original idea that isn't his. Forget about it and thanks for sharing. Mike

(in reply to flyncajun)
       Post #: 31

RE: Knife edge trimming question - 5/22/2008 1:15:39 PM   
dick Hanson



Posts: 10028
Joined: 12/12/2001
From: slc, UT, USA
Status: online
quote:

ORIGINAL: flyncajun

a wing has to produce lift ,,so I add positive inc. in the wing ,,not the fuse ,,like your set up requires.The airplane don`t know up,down sidways ECT we do ,
.
I challange you to try it 1/2 deg pos. to the centerline of the fuse start there,,and play around with it.



well -Iwon't even suggest you change your methods of trimming -it works for you
here is a point to consider tho:
by changing the angle of the wing - you do not change the lift the wing produces -as you noted . It simply changes relative angles to stab and fuselage
the wing will assume the correct angle for lift required -all on it's own.
Ask George Hicks -
I know you don't believe me.
Example:
IF a model weighs 11 lbs -the wing must assume an angle which produces 11 lbs lift -for level unaccelerated flight at a given speed..
IF you shim the wing up 1/2 degree- it STILL flies at that angle.
However all the rest of the airframe now is at 1/2 degree LESS angle to direction of flight. (this is why you reduce your downthrust )
The horizontal stab (elevator) must reduce effective angle to maintain the necessary downforce for the new wing position.
Changing the CG changes ALL of this.
Except
the wing always flies at the same angle if the speed and weight (effective weight ) is a constant.


< Message edited by dick Hanson -- 5/22/2008 1:32:15 PM >

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(in reply to flyncajun)
       Post #: 32

RE: Knife edge trimming question - 5/22/2008 2:17:26 PM   
flyncajun


 

Posts: 120
Joined: 12/25/2006
From: DENHAM SPRINGS , LA, USA
Status: offline 		Thanks Alp, i`m glad you had good results
And lord knows I want to stay in good with the Mafia
thanks Guys
Hey it was just a challenge to Dick , if I handed him a perfectly trimmed airplane he would say it could not be done
I like debating with him ,,,and he likes a good debate ,I don`t take it personal
I know George Hicks a real aero,,dynamist unlike me
But he still has not produce an airplane for pattern,, just foamies
Look!,, I`m glad I could help those I have ,,,
the proof is in the results.
Bryan

(in reply to alpbak)
       Post #: 33

RE: Knife edge trimming question - 5/22/2008 2:44:05 PM   
dick Hanson



Posts: 10028
Joined: 12/12/2001
From: slc, UT, USA
Status: online 		As long as you are happy, what else matters - You were a bit off about bro Hicks tho - he really does understand pattern models
very well-

< Message edited by dick Hanson -- 5/22/2008 2:47:21 PM >

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       Post #: 34

RE: Knife edge trimming question - 5/22/2008 3:06:14 PM   
flyncajun


 

Posts: 120
Joined: 12/25/2006
From: DENHAM SPRINGS , LA, USA
Status: offline 		Hey Dick
I know George ..I know he understands Pattern models very nice, and highly educated guy
just a little tounge -in -cheek.
btw .where is his trim guide
George scolded me pretty hard a few years back ,,,{well deserved I might add }
on talking above my pay
Everyone has methods that works for them
I`m just trying to share some methods that work for everyone
Dick I know you like to tinker ,,,just thought you would be interested in proving me wrong
with the results
Bryan

(in reply to dick Hanson)
       Post #: 35

RE: Knife edge trimming question - 5/22/2008 3:26:22 PM   
tggilkey


 

Posts: 129
Joined: 11/26/2003
From: Mendota Hts., MN, USA
Status: offline 		Hey everyone!

Alpbak It's been a good thing for all of us that you asked your question and your timing for me was perfect just finished a Genesis with the same symptoms you had. I haven't had the time to go into trimming mode yet but that will happen (actually haven't been flying much this Spring 5 flights on three different occasions engine issues). I'm looking forward to getting the plane sorted out.

Dean P. your detailed writings ( in FM over the years) have laid the gound work for things beginning to jell for me now having looked over Bryan's steps Thanks!!

Bryan we're looking forward to the video. I hope it's availablility is made well known up here in flyover country we don't find out about things until they are out of stock or out of production...

Thanks to all of you!!!
Tom

(in reply to flyncajun)
       Post #: 36

RE: Knife edge trimming question - 5/22/2008 4:18:13 PM   
dick Hanson



Posts: 10028
Joined: 12/12/2001
From: slc, UT, USA
Status: online
quote:

ORIGINAL: flyncajun

Hey Dick
I know George ..I know he understands Pattern models very nice, and highly educated guy
just a little tounge -in -cheek.
btw .where is his trim guide
George scolded me pretty hard a few years back ,,,{well deserved I might add }
on talking above my pay
Everyone has methods that works for them
I`m just trying to share some methods that work for everyone
Dick I know you like to tinker ,,,just thought you would be interested in proving me wrong
with the results
Bryan

Nothing to proove , you like the results you get, using your own approach.
As for tinkering ? well you could say that -
I tinkered my way into some commercially sucessful machine design patents and some models which sold well for many years - A tinkerer ? sure , why not


_____________________________

I am watching you
Libby

(in reply to flyncajun)
       Post #: 37

RE: Knife edge trimming question - 5/22/2008 9:15:53 PM   
mjfrederick


 

Posts: 587
Joined: 8/18/2006
From: Baton Rouge, LA, USA
Status: online 		Tom, I want to wish you luck with the Genesis. I understand a few modifications were done since the original production runs, so hopefully you will have better luck than we did with it. Unfortunately there are still inherent problems with the Genesis design that prevent it from achieving a truly mix-free setup (just ask the Chicago Mafia about their experiences) If you get it down to 5-7% rudder - up elevator (and that's all), you're doing really well. Everyone I know who has ever flown a Genesis complains that it drops the nose on rudder input.

Dick, I've had many a conversation with Bryan regarding aerodynamics and trimming (in fact, I edited the K-Factor article for him), and he does not disagree that the angle of attack required to produce lift at a given speed does not change regardless of whether using a 0-0 setup or a positive incidence setup. One thing I have seen and felt from flying his designs with his setups is that his airplanes roll, snap, spin, and lock into a line better than any other planes I've ever seen or flown, with less effort by the pilot, and throughout the maneuvering speed range. Whether at 1/4 or 3/4 throttle, the plane performs the same, only requiring the pilot to adjust the timing of control inputs. I wouldn't knock a 0-0 setup, to each his own... but I'd never fly one again after flying Bryan's.

Matt

_____________________________

mjfrederick AMA 275874 NSRCA 4134
Maybe the Dingo ate your baby

(in reply to dick Hanson)
       Post #: 38

RE: Knife edge trimming question - 5/22/2008 9:28:03 PM   
tggilkey


 

Posts: 129
Joined: 11/26/2003
From: Mendota Hts., MN, USA
Status: offline 		Hey Matt

Hmmm - my Genesis is from that same batch as the Chicago guys - I'll fix what I can and mix a little and finish the Impact... Thanks for the heads up.

Tom

(in reply to mjfrederick)
       Post #: 39